After seeds have been deposited in a trench formed by a pair of opener discs, it is desirable to press the seeds gently down into the soil at the bottom of the trench before the trench is then covered over with soil by the trailing press wheel. A variety of small firming wheels have heretofore been provided by various manufacturers for accomplishing this function.
However, one nagging problem is the accumulation of trash residue and mud in and around the firming wheels. When the buildup of this type of material becomes great enough, it will actually interfere with the rolling action of the wheel and may cause it to stop rolling all together, turning the wheel into more of a gouging device than something that gives the seed its final setting into place. The residue, mud and moisture can also cause premature failure of the bearing assembly of the wheel.